"When smoke was detected in two of the toilets ... the captain decided to divert the aircraft as a precautionary measure and land in Jakarta in order to allow the authorities to assist him to conduct a security assessment of the situation," said the airline in a statement.

After a search of the aircraft, passengers and carry-on luggage, the flight took off from Jakarta, continuing to Abu Dhabi.

Etihad Airways, the national carrier of the United Arab Emirates, didn't say whether any passengers were removed from the flight in Jakarta.

According to an updated statement from the airline, 12 passengers are being held by Abu Dhabi security authorities.

No arrests have been made.

More smoke

Despite strict controls over passenger movements instituted by the pilot, that wasn't the end of the smoking bathrooms.

Yet another toilet smoke alarm went off two hours before arrival in Abu Dhabi.

At this point, flight attendants ceased normal service to take up watch at each restroom and to monitor passenger access, said the airline.

The plane landed in Abu Dhabi four hours behind schedule.

No injuries were reported.

First person account

While Etihad Airways' official statement made no mention of an arsonist -- simply noting that smoke had been detected on board -- several passengers say they were told upon landing in Jakarta that someone had started fires on the plane.

Passenger Graham Foote, a singer traveling to Abu Dhabi for a performance, told CNN he became aware of the issue when cabin lights suddenly came on five hours into the flight.

"I looked at the inflight map and discovered that we were 90 minutes out from our destination, which seemed unusual given it's a 13-hour flight," said Foote.

"The captain then came over the intercom and announced that there had been a security breach and that we were diverting to Jakarta."

Other passengers say the reason for the diversion was explained to them only after landing in Jakarta.

"Upon arrival in Jakarta, we were told that a passenger had attempted to light two fires on the aircraft," said Foote.

When more smoke began coming from the bathroom following the Jakarta takeoff, all semblance of normal service -- including food and drink service -- was abandoned.

"Approximately two hours (away) from Abu Dhabi, we were informed that the arsonist had made another attempt and that all service was to be suspended," said Foote.

"The cabin staff also further restricted bathroom access at this point, checking the trash and toilet after every passenger had been inside."

Suspects

While the Sydney Morning Herald reports that a female passenger is a suspect, Foote said that two men "of Middle Eastern origin" seemed to be the subjects of investigation and were detained by police upon arrival in Abu Dhabi.

"One of the guys had a very nervous demeanor and intermittently changed seats throughout the flight from directly in front of me to another vacant seat with his travel companion," said Foote.

"During the first flight, when he entered the bathroom about seven staff members were congregated around the area, two of whom held fire extinguishers."

Upon landing at Abu Dhabi Airport, all passengers and crew were interviewed by authorities.

Etihad Airways has not commented on suspects, stating only that the event is still under investigation.